1. Field of the Invention
This invention relates to electrical packages, and more particularly, to an electronic pin grid array assembly.
2. Description of the Prior Art
A typical pin grid array assembly 10 of the prior art is shown in FIG. 1. Such an assembly 10 includes a pin grid array 11 having a body 12, which typically may be of molded or ceramic material, and which defines a plurality of holes 14 in which are rigidly fitted pins 16. These pins 16 extend entirely through the body 12 and beyond the opposite sides or surfaces 18, 20 thereof. Further included in the assembly 10 is a circuit board or base 22 which includes a plurality of passages 24 therethrough from one side or surface 26 thereof to the opposite side or surface 28. The positions of the passages 24 generally correspond to the positions of respective pins 16 of the pin grid array 11. The circuit board 22 has, in these passages 24, conductive metal material 30 which extends into metal conductors 32, 34, 36 on the opposite surfaces 26, 28 of the circuit board 22. The surface 26 also has disposed on it other metal conductors 37, 38, 39, 40 and metal pads 42, 44, 46 for the placement and fixing of semiconductor devices in the form of semiconductor chips 48, 50, 52, respectively. Wires 54 connect the metal conductors 32, 36, 37, 38 with the semiconductor chips 48, 50, 52, as is well known.
In the assembly 10, the pin grid array 11 and circuit board 22 are brought together to bring the ends of the pins 16 extending beyond surface 18 into respective openings 56 defined by the metal material 30. Solder 58 is applied into the openings 56 to connect the circuit board 22 with the pin grid array 11. The ends of the pins 16 which extend beyond the surface 20 can then be fitted to an interconnection board, as is well known.
A problem with this type of assembly is that a substantial amount of area of the surface 26 of the circuit board 22 cannot be used for the placement of semiconductor chips because the 16 pins and their associated structure (i.e., the metal material 30 and solder 32) preclude their placement in such area. Furthermore, addition of pins makes this problem even more extreme, taking up more such valuable area of the circuit board 22, which could with advantages be used for the placement of active and passive electronic devices.
It will furthermore be seen that the assembly 10 has the disadvantage that once solder 58 is placed in the openings 56 to connect the circuit board 22 with the pin grid array 11, these components cannot readily be separated.